MILAN, Italy — Milan yesterday joined London, Stockholm, and Singapore among cities imposing congestion charges on drivers in an effort to improve the air quality in one of Europe’s most polluted urban centers.

The nation’s fashion capital introduced a traffic charge of between two and 10 euros (about $3-14) for vehicles entering the city’s eight square-kilometer center for the most polluting models. Electric, hybrid, and some low-polluting cars are exempt. The city is seeking to raise 24 million euros a year (about $35 million) and will invest about two-thirds of the take in improving public transportation.

Mayor Letizia Moratti of Milan, a former education minister in Silvio Berlusconi’s latest government, has been pushing for the congestion charge since she took office in May 2006 as part of a broader plan to cut pollution and improve traffic in Italy’s second-biggest city.

Prime Minister Prodi’s government, the Lombardy region, and the local province have joined the mayor’s efforts with a 30-measure investment program worth 3.5 billion euros (about $5.2 billion), which also includes doubling the metro network by 2015, financing car-sharing and cycle tracks, replacing older heaters, and district heating.

Ms. Moratti has faced opposition from her own political allies to the measure and has had to scale down the original plan, which extended the charge to 60 square kilometers, or one third of the city area. The mayor has also had to postpone implementing the measure, which was scheduled to start in October, and was forced to include discounts for local residents. The final area represents 5% of the city.

About 90,000 cars cross the charge area daily, where 13% of daily car journeys take place, according to the city’s Web site. That compares with 4.8 million journeys inside and through the external Milan borders, of which less than a third is by public transport. The city aims to curb particle matter circulation in the center by 30%. More than 39,000 cars today entered the monitored zone between 7:30 a.m. and 5:00 p.m., according to a statement Ecopass sent by e-mail yesterday. An additional 8,000 commercial vehicles also entered the area.

Milan has the third-highest concentration of particle matter, known as PM10, among large European cities, both in terms of average annual level and days of breaching a European Union limit of 50 micrograms per cubic meter, according to a 2007 study of 26 European cities by the environmental group Legambiente and the research institute Ambiente Italia, and sponsored by Dexia SA. Particle matter pollution mainly originates from traffic, heating, and industries.

More than half of Milan citizens use private cars and motorbikes, the second-largest share among large European cities, after Rome, the study shows.